Low-water alarm for steam boilers



Oct. 23 1923.

w. A. MQKEOWN LOW WATER ALARM FOR STEAM BOILERS 1 Filed May 2, 1921 Patented Got. 23, i923.

barren srares i innate PATENTIOFFICE. ,g

' WILLIAM A. McKEown, or COLUMBUS, on'ro.

LOW-WATER ALARM FOR STEAM BOILERS.

1'0 all whom it may] concern Be it known that I, WILLIAM A. Mo-

KnowN, a citizen of the United States, resid-' ing at Columbus, in the county of Franklin and State of Ohio, have invented certain new and useful Improvements in Low-WaIter Alarms for Steam Boilers, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to improvements in low-water alarms for steamboilers, having for its object to providean effective safety device for this purpose, which willbe readily adaptable to locomotive, marine,.sta-

tionary, or portable types, of boilers, and equally applicable ,in principle to vat's or drawing the fire from the boiler or blowingoff the steam and water.

My invention as herein illustrated, is shown as appliedto the boiler of a locomotive and in a form of construction suitable for steam or air'pressure operation of the alarm which is here shown in the form of a whistle located, preferably, inthe engineers cab of the engine. It will be obvious, of course, that any suitable signal, as a bell or light, may be substituted for the whistle and that electrical connections may be used with equal facility to operate the alarm'when the water in the boiler is reduced to a predetermined level where safety of operationrequires a further supplyof water.

The invention, as here shown, comprisies but few simple parts and is, therefore, cheap to manufacture and to install, and, having direct connections and positive action, the mechanism is dependable and effective as to operation. 7

In the drawings only such detail parts of construction of a locomotive boiler are shown as are essential to properly illustrate the construction and operation of the inven" v upwardly on shaft 10- and. to project the o tion.

Application filed May 2, 1921. Serial No. 466,321.

As here shown Fig. 1 is a detail view in transverse section 2' through the roof sheet and crown sheet of a locomotive boiler showing 1 my improved alarm mechanism as'applied thereto, and the connections to the alarm signal; i

Fig. 2 is an enlarged detaillview of the lower portion of the'alarm mechanism adj acent the crownsheet, and

' Fig. 3' is a detail View ofa fusibleelement comprised in the mechanism detailed in Fig. 2. I

Fig. sis a view in verticalsection of a detail of the mechanismillustrated in;Fig. 2. The assembly of the alarm mechanism," as

hereshown, comprises the crownsheet 1 and roof sheet 2 of the locomotive boiler, the low-water level in the boiler beingindicated at 3.. The housing or casing for the alarm mechanism consists of a tube or'pipe section l, enlarged somewhat at its lower end and" threaded to form a ,water-tightjuncture with the crown sheet as indicated at 5,

the upper end'of thetube being substantially smaller than the lower end to provide for. passing the tube endwise through the aperture in the crown sheet to bring its lower end into engagement with the threaded aperture 'in the lower plate,,the juncture I being then made by turning the tube into position and threading a screw cap on its upper end, the joints being-sealed in the usual manner to make the same water-tight.

Tube 4 is closed at its lower end with a screw plug 7 having'an aperture 8 extending therethrough, and. at its upper end with an apertured screw cap 9 which serves as a bearing and guide for shaft v10 which ex tends into tube 4; and has secured to its lower end, a fusible element, here shown in the form of a disc 11 which is provided with. opposite clearance notches 12 and intervening solid'portions 13 which are adapted to I engage opposite stop plugs 14: threaded into the lower, portion of tube l, thus to prevent displacementof'the disc and upward movement of shaft 10 as long as the disc'll re 5 mains intact. 1

Shaft 10 extends beyond cap 9 andhasits upperend threaded to receive a. retaining nut 10 for a spring base 15 which forms a seat for the upper end ofa compression spring 16 interposed between base 15 and cap9, and acting normally to exert pressure shaft upwardly when released at its lower end by fusing of disc 11.

As here shown, the upper end'of shaft 10 is adapted, when the shaft is released to engage the mechanism of a valve 17, which serves normally to close a steam or air pressure pipe 18 connected to the alarm whistle 19, and thus to open the valve and cause operation ofthe alarm to indicate the lowwater state in the boiler. Operation of the alarm will be continuous until the mechanism is again adjusted for repeat operation which is effected by removing shaft 10 from tube 4, securing a new fuse disc to the shaft and again inserting the shaft in the tube with the clearance notches 12of thedisc in alignment with the stops 14:, thus permitting the disc to clear the stops as it is lowered to position in the tube,the disc being brought into engagement with the stops by giving shaft 10 a quarter turn thus preventing upwardmo'vem'ent of the shaft as long as the fuse disc remains intact.

V The fusible element 11' may be formed of any suitable metal which will fuse at a given approximate temperature. Thus-the same may be supported in tube {L at any-desired I crown sheet of a boiler, a tube supported relative to the crown sheet, a shaft supported "in said 'tubeand operably connected to the signal, means to operate said shaft, a fusible element secured to the shaft, a stop secured in the tube adjacent the fusible element and normally cooperating therewith to prevent operation of said shaft, *said fusible elementhaving clearance providing for movement ofsaid shaft relative to the stop in one direction and portions adapted to engage the stop to prevent movement of the shaft in the oppositedire ction.

In testimony, whereof, I affix my signature. WVILLIAM A. M'cKEOlVN. 

